Deposition apparatus and methods

Abstract

A deposition apparatus (20) comprising: a chamber (22); a process gas source (62) coupled to the chamber; a vacuum pump (52) coupled to the chamber; at least two electron guns (26); one or more power supplies (30) coupled to the electron guns; a plurality of crucibles (32,33,34) positioned or positionable in an operative position within a field of view of at least one said electron gun; and a part holder (170) having at least one operative position for holding parts spaced above the crucibles by a standoff height H. The standoff height H is adjustable in a range including at least 22 inches.

What is claimed is: 
     
       1. A method for using a deposition apparatus ( 20 ) comprising:
 a chamber ( 22 ); 
 a process gas source ( 62 ) coupled to the chamber; 
 a vacuum pump ( 52 ) coupled to the chamber; 
 at least two electron guns ( 26 ); 
 one or more power supplies ( 30 ) coupled to the electron guns; 
 a plurality of crucibles ( 32 , 33 , 34 ) positioned or positionable in an operative position within a field of view of at least one said electron gun; and 
 a part holder ( 170 ) having at least one operative position for holding parts spaced above the crucibles by a standoff height H, 
 
       wherein:
 the standoff height H is adjustable in a range including 22 inches; and 
 the method comprises operating in a non-DVD mode comprising:
 controlling the process gas source and the vacuum pump to maintain an atmosphere of 3-30 Pa absolute pressure; and 
 controlling the electron guns and power supplies to 20 to 90 kV at 160300 kW per gun. 
 
 
     
     
       2. The method of  claim 1  wherein:
 a process gas inlet ( 59 ) is located at the bottom of the coating chamber remote of the crucibles. 
 
     
     
       3. The method of  claim 1  wherein:
 the range includes 8 to 25 inches. 
 
     
     
       4. The method of  claim 1  wherein:
 the range includes 15 to 22 inches. 
 
     
     
       5. The method of  claim 1  wherein:
 the part holder is mounted to a retractable sting shaft; and 
 the part holder is a rake having a pair of arms and, along each arm, a plurality of rotary part-holding stations. 
 
     
     
       6. The method of  claim 1  wherein:
 the plurality of crucibles comprises a first set of crucibles and a second set of crucibles; and 
 an actuator is coupled to the first and second sets of crucibles and shifts the first and second sets into and out of the operative position. 
 
     
     
       7. The method of  claim 6  wherein:
 each of the plurality of crucibles has an associated ingot loader; 
 the ingot loaders of the first set are different from the ingot loaders of the second set; and 
 the ingot loaders of the first set carry ingots of different composition than do the ingot loaders of the second set. 
 
     
     
       8. The method of  claim 1  wherein:
 the crucibles contain a ceramic melt. 
 
     
     
       9. The method of  claim 1  wherein one or more of:
 the apparatus further comprises a pump and flow controller feedback system controlling the chamber pressure within +/−7% of setpoint pressure over the full range of process gas flowrates from 100 sccm to 100 slm; and 
 the power supply is switched between operation in the range 20-40 kV to operating in the range 41-80 kV, with no change in power delivered to the coating chamber. 
 
     
     
       10. The method of  claim 1  wherein:
 the part holder holds a plurality of vane doublets, each comprising an inboard shroud and an outboard shroud and a pair of airfoils therebetween; and 
 parts are rotated around their radial axis at a constant rotation rate from 4 to 120 rpm, while simultaneously being tilted over a range from −45 to +45 degrees. 
 
     
     
       11. The method of  claim 1  wherein:
 the part holder holds a plurality of blades, each comprising:
 an airfoil having a substrate having a leading edge, a trailing edge, a pressure side, and a suction side and extending from an inboard end to a tip; and 
 an attachment root; and 
 
 parts are rotated around their radial axis at a constant rotation rate from 4 to 120 rpm, while simultaneously being tilted over a range from −45 to +45 degrees. 
 
     
     
       12. The method of  claim 1  wherein:
 the process gas is introduced via a process gas inlet ( 59 ) located at the bottom of the coating chamber remote of the crucibles or along a wall of the coating chamber. 
 
     
     
       13. A method for operating a deposition apparatus ( 20 ), the deposition apparatus comprising:
 a chamber ( 22 ); 
 a process gas source ( 62 ) coupled to the chamber; 
 a vacuum pump ( 52 ) coupled to the chamber; 
 at least two electron guns ( 26 ); 
 one or more power supplies ( 30 ) coupled to the electron guns; 
 a plurality of crucibles ( 32 , 33 , 34 ) positioned or positionable in an operative position within a field of view of at least one said electron gun; and 
 a part holder ( 170 ) having at least one operative position for holding parts spaced above the crucibles by a standoff height H, the method comprising operating in a non-DVD mode comprising: 
 adjusting the standoff height H to a value in the range of 15 to 25 inches; 
 controlling the process gas source and the vacuum pump to maintain an atmosphere of 6.6 Pa to 30 Pa absolute pressure, the controlling of the process gas source resulting in flowrates of 3 to 100 slm introduced remote of the crucibles; 
 and 
 controlling the electron guns and power supplies to 20 kV to 90 kV at 160-300 kW per gun. 
 
     
     
       14. The method of  claim 13  wherein:
 the standoff height is 22 inches. 
 
     
     
       15. The method of  claim 13  wherein:
 process gas flowrates, if any, through or more process gas manifolds near the crucibles or near the parts, if any, is from 100 to 1000 sccm. 
 
     
     
       16. The method of  claim 15  wherein the operating is operating in a first mode and further comprising operating in a second mode by:
 adjusting the standoff height H to a value in the range of 8 to 18 inches and lower than said value in the range of 15 to 25 inches; and 
 controlling the process gas source and the vacuum pump to maintain an atmosphere of at most 2.0 Pa absolute pressure. 
 
     
     
       17. The method of  claim 13  wherein:
 the part holder holds a plurality of vane doublets, each comprising an inboard shroud and an outboard shroud and a pair of airfoils therebetween; and 
 parts are rotated around their radial axis at a constant rotation rate from 4 to 120 rpm, while simultaneously being tilted over a range from −45 to +45 degrees. 
 
     
     
       18. The method of  claim 17  wherein:
 the standoff height is 22 inches. 
 
     
     
       19. The method of  claim 13  wherein:
 the part holder is mounted to a retractable sting shaft. 
 
     
     
       20. The method of  claim 13  wherein:
 the part holder is a rake having a pair of arms and, along each arm, a plurality of rotary part-holding stations. 
 
     
     
       21. The method of  claim 13  wherein:
 the process gas is introduced at said flowrates via a process gas inlet ( 59 ) located at the bottom of the coating chamber remote of the crucibles or along a wall of the coating chamber.